Lubricated cutter mounting



Sept 26, 1939 A. c. cATLAND 2,174,102

LUBRICATED CUTTER MOUNTING Filed March 9, 1938 55 5:1114; 5713 wf/yPatented Sept. 26, 1939/y UNITED STATES PATENT OFFICE LUBRICATED CUTTERMOUNTING Alfred C. Catland, Alhambra, Calif., assignor to Globe OilTools Company, Los Nietos, Calif., a corporation of CaliforniaApplication March 9, 1938, Serial No. 194,779

8 Claims.

5 provide an improved long-wearing self-lubricated bearing or mountingfor the rotatable cutter of a well drilling tool.

The bearings of the cutters provided on rotary well drilling tools wearvery rapidly due to the 10 abrasive action of the rotary mud andcuttings in the Well and in some instances wear out before the teeth ofthe cutters. Attempts have been made to exclude the well iiuids from thecutter bearings by providing the bearings with packing washers andlsimilar sealing` means. Such attempts have been successful in part butit has been found that the well fluid and thc abrasive matter nds itsway into the bearings around or past the packing washers and causesexcessive wear of the bearings.

Another object of this invention is to provide a bearing for a cutter ofa well tool that embodies means for maintaining the bearing packed orlled with lubricant whereby the well uids and abrasive matter cannotreach the active' bearing parts.

Another object of this invention is to providel a cutter mounting orcutter bearing that may be completely packed with lubricant before thewell tool is run into the well and that has means for automaticallyintroducing more lubricant to the bearing as the tool is operated,thereby eliminating any air pockets that may be present in the bearingand maintaining a pressure on the lubricant in the bearing to preventthe entrance of abrasive matter.

Another object of this invention is to provide a cutter bearing of thecharacter mentioned embodying a novel pump means operated by therotating cutter that feeds or forces lubricant to the active parts ofthe bearing as the tool is operated in the well.

Another object of this invention isto provide a bearing means of thecharacter mentioned in which the lubricant in the bearing is maintainedunder a pressure equal to or greater than the pressure on the well uidso that the well fluid is prevented from entering the bearing.

Another object of this invention is to provide a cutter mounting orcutter bearing of the character mentioned in which the lubricator orlubricating means is entirely contained in the bearing, making itunnecessary to provide ports or passages in the tool body and materiallysimplifying the general tool construction.

(Cl. Z55-71) A further object of this invention is to provide a cutterbearing of the character mentioned in which the lubricating means issimple and inexpensive to manufacture and does not materially complicatethe bearing construction.

The various objects and features of my invention will be fullyunderstood from the following detailed description of a. typicalpreferred form of the invention, throughout which description referenceis made to the accompanying drawing 10 in which:

Fig. 1 is a side elevation of a rotary well drilling tool with a portionbroken away to illustrate a cutter mounting means of the characterprovided by the invention. Fig. 2 is an enlarged 15 fragmentary verticaldetailed sectional view of the bearing means, the cutter and theadjacent parts. Fig. 3 is an enlarged fragmentary `detailed sectionalview taken as indicated by line 3--3 on Fig. 2 showing the camapproaching the 20 valve. Fig. 4 is a view similar to Fig. 3 showing thecam actuating the valve. Fig. 5 is an enlarged fragmentary verticaldetailed sectional view of the bearing means showing the pump mechanismand Fig. 6 is an enlarged fragmen- 25 tary transverse detailed sectionalView taken as indicated by line 6-6 on Fig. 5.

The cutter bearing means or mounting means of the present invention maybe embodied in well tools of various types and may be employed to 30carry or support rotating cutting elements of different forms. In thedrawing I have shown the invention embodied in a bearing for the rollercutter of a well drilling bit. It is to be understood that the inventionis not to be con- 35 strued as limited or restricted to the speciiicform or application of the invention about to be described but that itis to be taken as including any features or modifications that may fallwith- Ain the scope of the claims. 40

The well bit illustrated in the drawing is a rotary well drilling toolcomprising a body I0 to be connected with the lower end of a rotary welldrilling string. The body I0 has sets of spaced depending legs II and I2and cutters I3 45 are arranged between the legs Il and I2. The opposingsurfaces of the adjacent legs Il and I2 slope downwardly and outwardlywith respect to the central vertical axis of the bit. The cutters I3 aretapered or truste-conical roller cutters 50 having peripheral cuttingteeth I4. Central longitudinal openings I5 extend through the cuttersI3. The cutters I3 are the outer cutters oi the bit and the bit includescross cutters or inner cutters I6. The bearing means for the several 55cutters of the bit may be similar or identical and I will proceed with adetailed description of the means for rotatably supporting one of thecutters I3, it being understood that such description may apply to thebearings for the other cutters. o

The lubricated cutter mounting means of the present invention includes,generally, a supporting pin I1 extending between two spaced legs II andI2 and having a lubricant chamber I8, a bushing or bearing member I9 on.the pin I1 within the opening I5 of a cutter I3, anti-friction membersor parts 20 supporting the cutter I3 on the bearing member I9 and means2I operated by the rotating cutter I3 to pump or deliver lubricant from.the chamber I8 to the opening I5 of the cutter.

The pin I1 is provided to carry the bearing member I9 and its cutter I3.The pin I1 extends between and is supported by the spaced parallel bodylegs II and I2. The leg II has a downwardly and inwardly inclinedtransverse opening 22 and the leg I2 has an aligned correspondinglyinclined opening 23. The pin I1 is passed outwardly through the opening22 and has its outer portion threaded in the opening 23. A suitable headis provided on the inner end of the pin I1 and is received in theopening 22. The outer end of the pin I 1 may be peened over at 24 toprevent the pin from becoming unthreaded.

The chamber I8 in the supporting pin I1 is provided to contain what maybe termed a secondary or auxiliary supply of lubricant. The chamber I8may be formed by drilling a longitudinal bore in the pin I1 from itsinner end and then closing the end of the bore with a plug 25. The plug25 may be welded to the pin I1 at 26. A longitudinal opening 21 isprovided in the Plug 25 to admit lubricant to the chamber I8. It ispreferred to provide the opening 21 with a valved fitting, As shown inthe drawing a suitable grease gun tting 28 may be threaded in theopening 21 and may have its outer part received in an enlarged endportion of the opening. The lubricant chamber I8 is preferably ofsubstantial length to contain a substantial quantity of the lubricant.

The bushing or bearing member I9 is received in the cutter opening I5with suitable clearance and is supported on the pin I1 between thespaced legs II and I2. The opposite ends of the member I9 may be flat tobear against the opposing sides or surfaces of the legs II and I2. Themember I9 may be a cylindrical spool-like member provided at its outerend with a radial .flange 30. The flange 30 is partiallyreceived 1n asocket 3I in the outer end of the cutter. Lugs 32 and 33 are provided onthe member I9 to cooperate with the lower ends of the legs II and I2,respectively. The lugs 32 and 33 serve to position the member I9 and toprevent it from rotating. The lug 33 may be welded to the leg I2 at 34.

The anti-friction members or parts 20 are provided to support the cutterI3 on the bearing member I9 for free rotation. In the preferredconstruction the anti-friction bearing parts 2B are in the nature ofballs. Spaced annular ball races 35 are provided in the wall ofthecutter opening I5 and oppose similar ball races 36 in the periphery ofthe bearing member I9. The balls 0r bearing parts 20' occupy the `pairsof spaced opposed races 35 and 36, there .being a series of the parts 20in each pair of races. The races 35 and 36 are of such depth that thebearing parts a 20 transmit end thrusts in both directions as well asthe radial thrusts and may form the sole means for rotatably supportingthe cutter I3 on' inserted in the races 35 and 36 plugs 39 are arrangedin the bores 31. The plugs 39 are passed into the bores 31 from theirinner ends and the outer ends of the plugs are shaped to formcontinuations of the-races 36. Keys 40 are provided on the inner ends ofthe plugs 39 and cooperate with keyways 4I formed in the wall of theopening 38 to prevent turning of the plugs and to limit outward movementof the plugs. The pin I1 cooperates with the inner ends of the plugs 39to limit their inward movement. The above described means forfacilitating the insertion of the balls or bearing parts 20 in the races35 and 36 is fully described and claimed in my co-pending applicationentitled Rock bit, Ser. No. 191,243, led February 18, 1938.

In accordance with the invention all the spaces within the bearing andcutter assembly are lled with lubricant before the assembly is mountedon the bit body I0 and before the bit is run into the well. This packingof the cutter and bearing assembly with lubricant is carefully done toeliminate as far as possible voids or air spaces in the assembly.Packing means are preferably incorporated in the assembly to prevent orlessen the loss of the lubricant and the entrance of the well fluids tothe bearing. An annular groove 42 is provided in the inner side of theflange 30 to oppose the adjacent end of the cutter I3. A washer 43 offelt or the like is arranged in the groove 42 to seal with the wall ofthe socket 3I in the end of the cutter I3. The Washer 43 prevents orreduces the loss of lubricant outwardly between the cutter I3 and theflange 30 and prevents or lessens the entrance of well fluid into theouter end of the bearing. An annular groove 44 is provided in theperiphery of the member I9 adjacent its inner end and a washer 45 offelt or the like is set in this groove to seal with the wall of thecutter opening I5. The washer 45 serves to prevent or lessen the loss oflubricant from the inner end of the cutter opening I5 and to prevent orlessen the entrance of well uid to the openings.

The means 2| is provided to discharge or force lubricant from thechamber I8 to the cutter opening I5 to remove all voids or air spaces inthe bearing and to maintain the bearing charged or full of lubricant asthe tool is operated in the well, to materially reduce the friction andto prolong the life of the bearing. 'I'he means 2| includes a followeror piston 46 in the lubricant chamber I8. The piston 46 faces and movestoward the plug 25 and is urged against the bodyv of lubricant in thechamber I8 by a spring 41. The spring 41 is arranged under compressionbetween the'piston 46 and the adjacent end wall of the chamber I8. Aport 48 extends through the pin I1 from said end wall of the chamber -IIto the outer end of the pin to place the end portion of the chamber I8in communication with the Well. The port 49 permits the pressure on theduid in the well to 'act against thepiston 46 and the lubricant in thechamber I8 and to maintain the pressure on the lubricant in the bearingequal to or in excess of the external pressure as will be more fullydescribed.

The means 2I further includes an ejecting .mechanism or pump mechanismfor forcing lubricant from the supply chamber I8 to the opening I5 inthe cutter I3 to lubricate the anti-friction parts 20 and the races 35and 36. An annular groove 49 is formed in the periphery of the pin I1and a port 58 is provided in the pin. to extend from the chamber I8 tothe groove 49. The port 50 preferably has its inner end adjacent theplug 25. A cylinder opening 5I is provided in the bearing member I9 andextends through the wall of the member Yfrom its opening 38 to itsperiphery. It is preferred to provide the cylinder opening 5I in thelower portion of the member I9 so that the lubricant passed therethroughis delivered tothe loaded side of the bearing. 'Ihe outer end of thecylinder opening 5I is spaced between the races 36 and the inner end ofthe opening 5I communicates with the groove 49. The outer portion of thecylinder opening 5I is reduced in diameter to provide an inwardly facingshoulder or seat 52 on the wall of the opening.

An insert or annular valve seat 53 is force-fitted or otherwise securedin the inner portion of the cylinder opening 5I. An inwardly seatingball 5`4 cooperates with the seat 53 to control the introduction oflubricant from the groove 49 to the opening 5I. The ball 54 may betermed a' foot valve. A tapered valve 55 seats outwardly against theseat 52 to control the discharge of lubricant from the opening 5I to theopening I5 in the cutter I3. The valve 55 has a stem 56 extendingoutwardly through the cylinder opening 5I to project from the peripheryof the bearing member I9. The stem 56 is grooved or triangular in crosssection to allow for. the passage of lubricant outwardly past or aroundit. 'I'he stem 56 slidably cooperates with the wall of the reducedportion of the opening 5I to guide the valve 55. Spring means isprovided to urge the valves 54 and 55 to their closed positions. Ahelical spring 51 is arranged in the opening 5I and is under compressionbetween the ball valve 54 and the valve 55. The spring 51 normally holdsthe two valves 54 and 55 closed and is yieldable to allow the valves toopen.

The means 2| includes a cam means to operate or reciprocate the valve 55to create a pumping action in the cylinder opening 5I and to dischargelubricant from the opening 5I into the cutter opening I5. The outer endof the valve .stem 56 is tapered or rounded. The valve 55 cooperateswith the seat 52 to limit the outward travel of the stern 56 and itscooperation with'the seat normally holdsthe stem 56 where its outer endclears the wall of the opening I5. A cam 58 is provided on the wall ofthe opening I5 to cooperate with the valve stem 56. In practice the cam58 may be welded on the wall of the opening I5.. The active face 59 ofthe cam 58 slopes gradually from the wall of the opening I5 rearwardlyrelative to the direction of rotation of the cutter I3. The sloping camface 59 cooperates with the. end of the valve stem 56, once during eachrevolution of the cutter to force the valve 55 inwardly from its seat52. This inward movement of the valve 55 is accompanied by the dischargeof lubricant from the opening 5I to the cutter opening I5.

During the operation of the bit the bit body I is rotated and feddownwardly in the usual manner so that the cutters I3 and I6 rotate ontheir axes and roll on the earth formation at the bottom of thewellbore. Referring to the cutter I3 and its bearing means described indetail above, thebearing for the cutter is thoroughly packedwith greaseor other lubricant before the assembly is applied to the bit body I0.The chamber I8 is charged or lled with a supply of lubricant. duced tothe. chamber I8 under pressure by a grease gun or the like connectedwith the ftting 28. In practice the chamber I 8 may be completely lledwith the lubricant to move the piston 46 to a position such asillustrated in Fig. 2 of the drawing. Following the charging of thechamber I8 the tting 28 may be sealed off with welding or the like ifthis is believed necessary. It is to be understood that the chamber I8and the port 50, the groove 49 and the opening 5I communicating with thechamber and the cutter opening I5 are all lled or packed with thelubricant.

When the tool is operated in the well in the presence of the well liquidunder pressure the external pressures act on the lubricant in thechamber I8 through the medium of the piston 46. The external pressuresare admitted through the port 48 to act on thel piston 46. Thus thelubricant in the chamber I8 and the other parts of the bearing aresubjected to a vpressure at least equal to the external pressures. Thepressure on the lubricant in the chamber I8 and in the other parts ofthe bearing is augmented or increased by the spring 41 forcing thepiston 46 against the. charge of lubricant in the chamber I8.Accordingly, the lubricant in the chamber I8 and in the other parts ofthe bearing is normally under a pressure greater than the external pres-Y sures, The lubricant under pressure in the opening I5 aids inpreventing the entrance of well liquid and abrasive matter to thebearing and the felt washers 43 and 45 assist in this action. The

The lubricant may be introfelt washers 43 and 45 also serve to lessen orprevent the loss of `the lubricant under pressure from the opposite endsof the cutter opening I5.

As the cutter I3 rotates through its engagement with the earth-formationthe cam 58 operates cr moves the stem 56 and the valve 55. The cam face59 moves the valve 55 inwardly during a,

short phase of each revolution of the cutter I3 sure in the opening 5Iis partially displaced by the inwardly moving valve and is allowed topass out around the valve stem 56 to enter the cutter opening I5. Duringthe closing or outward movement of the valve 55 a reduced pressurecondition is created in the opening 5I and lubricant under pressure fromthechamber I8 unseats the valve 54 -and ows' into the opening 5I.

The lubricant under pressure discharged from the opening 5I enters thecutter opening I5 at a point between the spaced races 36. This lubricantkeeps the anti-friction parts 20 and the races 35 and 36 lubricated atall times. The lubricant discharged from the opening 5I to the cutteropening I5 replaces any lubricant that may leak from the bearing duringoperation of the tool and keeps the bearing full of grease or lubricant.Further, the lubricant under pressure discharged from the opening 5lmaintains the lubricant in the bearing under a pressure equal to orgreater than the external pressure so that the well iluid and solidmatter has no opportunity to enter the bearing. Lubricant may beintermittently discharged from the opening 5I throughout the entire runof the drilling tool so that the anti-friction parts 20 operate in abath of lubricant. The bearing Supplied with replacement or additionallubricant throughout the operation of the cutter I3 is subject to aminimum of wear and friction and is long wearing.

Having described only a typical preferred form and application of myinvention I do not wish to be limited or restricted to the specific formand application herein set forth, but wish to reserve to myself anyvariations or modifications that may appear to those skilled in the artor fall within the scope of the following claims.

Having described my invention, I claim:

1. Means for lubricating a cutter assembly of a well drilling bit, theassembly including a cut ter having an opening, a supporting pin passingthrough the opening, and anti-friction bearing means carried by the pinand rotatably supporting the cutter, said lubricating means comprisingWalls in the pin defining a lubricant chamber, walls in said bearingmeans defining a passage for conducting lubricant from the chamber tothe cutter opening, there being port means in the pin subjecting thelubricant in the chamber to the well pressures to urge-it through thepassage, and spring means increasing said pressure on the lubricant.

2. Means for lubricating the assembly of a well bit cutter having anopening, a supporting pin passing through the opening, a bearing membcron the pin and spaced series of anti-friction parts rotatably supportingthe cutter on said member, the lubricating means comprising walls in thepin defining a lubricant chamber, walls in said member defining apassage for conducting lubricant from said chamber to the exterior ofthe member between said spaced series of parts, a spring urged piston inthe chamber feeding the lubricant to the passage, a pump element in thepassage for ejecting lubricant therefrom, and a cam on the Wall of thecutter opening operating the pump element.

3. Means for lubricating the assembly `of a lcutter having an opening, asupporting pin passing through the opening, a bearing member on the pinand spaced series of anti-friction parts rotatably supporting the cutteron said member, said lubricating means comprising Walls in the pindefining a lubricant chamber, walls in said member defining a passagefor conducting lubricant from said chamber to the exterior of the memberbetween said spaced series of parts, a spring urged piston in thechamber feeding the lubricant to the passage, a pump element in thepassage for ejecting lubricant, a foot valve in the passage preventingthe return of lubricant therefrom to the chamber, and a cam on the wallof the cutter opening operating the pump element.

4. Means for lubricating a well tool cutter assembly having a rotatableroller cutter, a bushing extending through the cutter and having alubricant duct leading to the interior of the cutter, and a pin carryingthe bushing and having a lubricant chamber communicating with the ductto supply lubricant thereto, the lubricating I means comprising pumpmeans in the duct operable to force the lubricant into the cutter, and apart on the cutter for operating the pump means during rotation of thecutter.

5. Means for lubricating a well tool cutter assembly having a rotatableroller cutter, a bushing extending through the cutter and having alubricant duct leading to the interior of the cutter, and a pin carryingthe bushing and having a lubricant chamber communicating with the ductto supply lubricant thereto, the lubricating means comprising, means forforcing lubricant from the chamber to the duct, pump means in the ductoperable to force the lubricant into the cutter, and a part on thecutter for operating the pump means during rotation of the cutter.

6. Means for lubricating a well tool cutter assembly having a rotatableroller cutter, a bushing extending through the cutter and having alubricant duct leading to the interior of the cutter, and a separablepin carrying the bushing and having a lubricant chamber communicatingwith the duct and a port leading from the chamber to the exterior of thepin to admit fluid pressure from` the well to the chamber, thelubricating means comprising a piston in the chamber acted on by saidfluid pressure to force the lubricant to the duct, a spring acting onthe piston to assist in said action of the fluid pressure, valve meanscontrolling the discharge of lubricant from the duct to the interior ofthe cutter, and a part on the cutter for opening the valve means duringrotation of the cutter.

7. Means for lubricating a well tool cutter assembly having a rotatableroller cutter, a bushing extending through the cutter and having alubricant duct leading to the interior of the cutter, and a separablepin carrying the bushing and having a lubricant chamber, a port in oneend communicating with the chamber to admit fluid pressure to thechamber and a port in the other end leading to the chamber, thelubricating means comprising a fitting at the last named port foradmitting lubricant to the chamber, a piston in the chamber acted on bythe said fluid pressure to force the lubricant from the chamber to theduct, valve means at the duct for controlling the discharge of thelubricant therefrom and a part on the rotating cutter for opening thevalve means.

8. Lubricating means for the assembly of a rotatable cutter, and atubular bushing in the cutter, the bushing having a duct leading fromits interior to the interior of the cutter, the lubricating meanscomprising a separable pin extending through the bushing and having alubricant containing chamber in communication with the said duct, pumpmeans at s aid duct for pumping the lubricant into the cutter, and apart on the cutter operating the pump means during rotation of thecutter.'

ALFRED C. CA'I'LAND.

